Foraminifera; sea level changes; monsoon; oxygen and carbon isotopes; Maldives; sequence boundaries; carbonates
Stainbank Stephanie, Kroon Dick, de Leau Erica S., Spezzaferri Silvia (2021), Using past interglacial temperature maxima to explore transgressions in modern Maldivian coral and Amphistegina bleaching thresholds, in
Scientific Reports, 11(1), 10267-10267.
Stainbank Stephanie, Spezzaferri Silvia, De Boever Eva, Bouvier Anne-Sophie, Chilcott Colin, de Leau Erica S., Foubert Anneleen, Kunkelova Tereza, Pichevin Laetitia, Raddatz Jacek, Rüggeberg Andres, Wright James D., Yu Siyao M., Zhang Manlin, Kroon Dick (2020), Assessing the impact of diagenesis on foraminiferal geochemistry from a low latitude, shallow-water drift deposit, in
Earth and Planetary Science Letters, 545, 116390-116390.
Stainbank Stephanie, Spezzaferri Silvia, Beccari Valentina, Hallock Pamela, Adams Arthur, Angeloz Aurelie, Basso Daniela, Caragnano Annalisa, Del Piero Nicolo, Dietsche Patrick, Eymard Ines, Farley Nicholas, Fau Marine, Foubert Anneleen, Lauper Bruno, Lehmann Anael, Maillet Marine, Negga Haileyesus, Ordonez Luis, Peyrotty Giovan, Rime Valentin, Rüggeberg Andres, Schoellhorn Iris, Vimpere Lucas (2020), Photic stress on coral reefs in the Maldives: The Amphistegina bleaching index, in
Ecological Indicators, 113, 106257-106257.
Beccari V., Spezzaferri S., Stainbank S., Hallock P., Basso D., Caragnano A., Pisapia C., Adams A., Angeloz A., Del Piero N., Dietsche P., Eymard I., Farley N., Fau M., Foubert A., Lauper B., Lehmann A., Maillet M., Negga H., Ordonez L., Peyrotty G., Rime V., Rüggeberg A., Schoellhorn I., et al. (2020), Responses of reef bioindicators to recent temperature anomalies in distinct areas of the North Ari and Rasdhoo atolls (Maldives), in
Ecological Indicators, 112, 106128-106128.
Stainbank Stephanie, Kroon Dick, Rüggeberg Andres, Raddatz Jacek, de Leau Erica S., Zhang Manlin, Spezzaferri Silvia (2019), Controls on planktonic foraminifera apparent calcification depths for the northern equatorial Indian Ocean, in
PLOS ONE, 14(9), e0222299-e0222299.
Kunkelova Tereza, Jung Simon J. A., de Leau Erica S., Odling Nick, Thomas Alex L., Betzler Christian, Eberli Gregor P., Alvarez-Zarikian Carlos A., Alonso-García Montserrat, Bialik Or M., Blättler Clara L., Guo Junhua Adam, Haffen Sébastien, Horozal Senay, Mee Anna Ling Hui, Inoue Mayuri, Jovane Luigi, Lanci Luca, Laya Juan Carlos, Lüdmann Thomas, Bejugam Nagender N., Nakakuni Masatoshi, Niino Kaoru, Petruny Loren M., et al. (2018), A two million year record of low-latitude aridity linked to continental weathering from the Maldives, in
Progress in Earth and Planetary Science, 5(1), 86-86.
Shahzad Khurram, Betzler Christian, Ahmed Nadeem, Qayyum Farrukh, Spezzaferri Silvia, Qadir Anwar (2018), Growth and demise of a Paleogene isolated carbonate platform of the Offshore Indus Basin, Pakistan: effects of regional and local controlling factors, in
International Journal of Earth Sciences, 107(2), 481-504.
ColettiGiovanni, StainbankStephaine, FabbriniAlessio, SpezzaferriSilvia, Foubert Anneleen, KroonDick, BetzlerChristian (2018), Biostratigraphy of large benthic foraminifera from Hole U1468A (Maldives): a CT-scan taxonomic approach, in
Swiss Journal of Geosciences, 111(3), 523-536.
| Author |
Stainbank, Stephanie; Spezzaferri, Silvia; Rüggeberg , Andres |
| Publication date |
01.09.2020 |
| Persistent Identifier (PID) |
https://doi.org/10.1594/PANGAEA.914883 |
| Repository |
Pangea
|
| Abstract |
Due to their large heat and moisture storage capabilities, the tropics are fundamental in modulating both regional and global climate. Furthermore, their thermal response during past extreme warming periods, such as super interglacials, is not fully resolved. In this regard, we present high-resolution (analytical) foraminiferal geochemical (δ^18^O and Mg/Ca) records for the last 1800 kyr from the shallow (487 m) Inner Sea drift deposits of the Maldives archipelago in the equatorial Indian Ocean. Considering the diagenetic susceptibility of these proxies, in carbonate-rich environments, we assess the integrity of a suite of commonly used planktonic and benthic foraminifera geochemical datasets (Globigerinoides ruber (white), Globigerinita glutinata (with bulla), Pulleniatina obliquiloculata (with cortex) and Cibicides mabahethi) and their use for future paleoceanographic reconstructions.Using a combination of spot Secondary Ion Mass Spectrometer, Electron Probe Micro-Analyzer and Scanning Electron Microscope image data, it is evident that authigenic overgrowths are present on both the external and internal test (shell) surfaces, yet the degree down-core as well as the associated bias is shown to be variable across the investigated species and proxies. Given the elevated authigenic overgrowth Mg/Ca (∼12-22 mmol/mol) and δ^18^O values (closer to the benthic isotopic compositions) the whole-test planktonic G. ruber (w) geochemical records are notably impacted beyond ∼627.4 ka (24.7 mcd). Yet, considering the setting (i.e. bottom water location) for overgrowth formation, the benthic foraminifera δ^18^O record is markedly less impacted with only minor diagenetic bias beyond ∼790.0 ka (28.7 mcd). Even though only the top of the G. ruber (w) and C. mabahethi records (whole-test data) would be suitable for paleo-reconstructions of absolute values (i.e. sea surface temperature, salinity, seawater δ^18^O), the long-term cycles, while dampened, appear to be preserved. Furthermore, planktonic species with thicker-tests (i.e. P. obliquiloculata (w/c)) might be better suited, in comparison to thinner-test counter-parts (i.e. G. glutinata (w/b), G. ruber (w)), for traditional whole-test geochemical studies in shallow, carbonate-rich environments. A thicker test equates to a smaller overall bias from the authigenic overgrowth. Overall, if the diagenetic impact is constrained, as done in this study, these types of diagenetically altered geochemical records can still significantly contribute to studies relating to past tropical seawater temperatures, latitudinal scale ocean current shifts and South Asian Monsoon dynamics.
| Author |
Kunkelova, Theresa; Stainbank, Stephanie; Rüggeberg, Andres |
| Publication date |
18.12.2018 |
| Persistent Identifier (PID) |
https://doi.org/10.1186/s40645-018-0238-x |
| Repository |
Pangea
|
| Abstract |
Indian-Asian monsoon has oscillated between warm/wet interglacial periods and cool/dry glacial periods with periodicities closely linked to variations in Earth's orbital parameters. However, processes that control wet versus dry, i.e. aridity cyclical periods on the orbital time-scale in the low latitudes of the Indian-Asian continent remain poorly understood because records over millions of years are scarce. The sedimentary record from International Ocean Discovery Program (IODP) Expedition 359 provides a well-preserved, high-resolution, continuous archive of lithogenic input from the Maldives reflecting on low-latitude aridity cycles. Variability within the lithogenic component of sedimentary deposits of the Maldives results from changes in monsoon-controlled sedimentary sources. Here, we present X-ray fluorescence (XRF) core-scanning results from IODP Site U1467 for the past two million years, allowing full investigation of orbital periodicities. We specifically use the Fe/K as a terrestrial climate proxy reflecting on wet versus dry conditions in the source areas of the Indian-Asian landmass, or from further afield. The Fe/K record shows orbitally forced cycles reflecting on changes in the relative importance of aeolian (stronger winter monsoon) during glacial periods versus fluvial supply (stronger summer monsoon) during interglacial periods. For our chronology, we tuned the Fe/K cycles to precessional insolation changes, linking Fe/K maxima/minima to insolation minima/maxima with zero phase lag. Wavelet and spectral analyses of the Fe/K record show increased dominance of the 100 kyr cycles after the Mid Pleistocene Transition (MPT) at 1.25 Ma in tandem with the global ice volume benthic δ18O data (LR04 record). In contrast to the LR04 record, the Fe/K profile resolves 100-kyr-like cycles around the 130 kyr frequency band in the interval from 1.25 to 2 million years. These 100-kyr-like cycles likely form by bundling of two or three obliquity cycles, indicating that low-latitude Indian-Asian climate variability reflects on increased tilt sensitivity to regional eccentricity insolation changes (pacing tilt cycles) prior to the MPT. The implication of appearance of the 100 kyr cycles in the LR04 and the Fe/K records since the MPT suggests strengthening of a climate link between the low and high latitudes during this period of climate transition.
The Maldivian archipelago is a pure carbonate environment in a subtropical, low-latitude setting and, as such, it is an ideal place to investigate the archive of past oceanographic changes and evaluate the timing of global sea-level changes in the Cenozoic. The International Ocean Discovery Program (IODP) Expedition 359 Maldives Monsoon and Seal Level (30.09 to 30.11, 2015) will drill the Cenozoic sedimentary sequence north of the Malé and Ari Atolls at seven sites Mal-01 to Mal-07. Aim of the expedition is to understand the evolution the Cenozoic icehouse world in the Indo-Pacific region, to reconstruct the processes that shape carbonate platforms and their stratigraphic records, to reconstruct the evolution of the Maldives, to reveal the influence of sea level changes and the role of the Indian Monsoon on these carbonate platforms. The focus of this proposal is to investigate the Cenozoic (Neogene) planktonic foraminifera that will be recovered during IODP Expedition 359. The Shipboard Scientific Party will preliminary investigate on board the recovered sediments with a multidisciplinary approach. A more detailed shore-based study will be conducted after the cruise and in collaboration with a broader international team. The micropaleontology group of the University of Fribourg is involved in this shore-based investigation and will benefit of the direct collaboration with Prof. Dick Kroon (University of Edinburgh) who is invited to sail. He will collect sample of about 10 cm3 volume on board the RV JOIDES Resolution at all drilled sites. These samples will be shared for investigation among the two institutions, Fribourg and Edinburgh, respectively. Samples will be prepared using standard techniques for qualitative and quantitative analyses on planktonic foraminifera and for oxygen and carbon isotopes analyses. Comparison of qualitative and quantitative planktonic data with shipboard data (e.g., magnetostratigraphy, physical properties) and the isotope record will contribute to improve the existing bio- and isotope stratigraphies and will highlight discrete relationship between assemblages and species ecology, thus improving existing time scales and providing a paleoceanographic reconstructions. The comparison of the isotope record through the Cenozoic with the seismic reflectors will have the potential to reveal the mechanisms that influenced sedimentation types and rate (e.g., eustatic sea level changes). The multispecies isotopes plots will give information about the living habitat of planktonic species, their evolution through time and their relation with the current circulation patterns, contributing therefore, to understand the role of the Indian Monsoon through time.The overall objectives of this project are to: produce detailed bio- isotope stratigraphies of the drift deposit recovered during the Expedition 359 and thus improve existing time scales; test if sea level changes documented in the Atlantic Ocean can be also traced in the Indian Ocean; test if the processes producing regional seismic reflectors were modulated by the same alternation of pelagic versus neritic/periplatform sedimentation and linked to eustatic sea level rises; reconstruct a paleoceanographic scenario that will contribute to understand the current circulation pattern and the influence of the Indian Monsoon in the Indian Ocean.This research will benefit of the collaboration with Prof. Dick Kroon, The Expedition 359 Scientific Party and the Neogene Planktonic Foraminifera Working Group.